172-65260m-05 (S-COS/S-COSR Pressure Reducing Valve) 27 Oct 2008
6
Correct Usage of S-COS / S-COSR Pressure Reducing Valve
Install properly and DO NOT use this product outside the recommended
operating pressure, temperature and other specification ranges.
Improper use may result in such hazards as damage to the product or
malfunctions which may lead to serious accidents. Local regulations
may restrict the use of this product to below the conditions quoted.
CAUTION
1. The pressure reducing valve should be operated only within its specifications.
2. Installing an ON / OFF Valve (Solenoid Valve or Motorized Valve)
If an on-off valve, such as a motorized valve, is required to stop supply of steam
to the steam-using equipment, install it at the inlet side of the pressure reducing
valve. If a solenoid valve is installed at the outlet of the reducing valve, its
opening and closing will cause heavy chattering and may lead to damage of the
piston and main valve. (When the on-off valve opens, the secondary pressure of
the reducing valve changes from zero to the set pressure. Passing through an
area of the reducing ratio of less than 10:1, where adjustment is impossible,
chattering occurs momentarily. To save energy, install the on-off valve as near to
the boiler as possible.
NOTE: To prevent water hammer, it is recommended that a slow-acting
motorized on-off valve be used. In particular, if a fast-acting on-off solenoid valve
is used for frequent temperature control, the potential water hammer effect can
damage the steam equipment and the pressure reducing valve.
3. Installing a Control Valve
A control valve installed between the pressure reducing valve and the steam
equipment (downstream of the reducing valve) for controling equipment
temperature may raise the pressure between the pressure reducing valve and
the control valve when the control valve is closed, depending on the spatial
relationship. A safety valve should be installed downstream of the control valve.
Note: When installing a safety valve to protect the steam equipment, be sure to
install it on the steam equipment or directly before the inlet of the steam
equipment. If the safety valve is installed on the outlet side of the pressure
reducing valve between the pressure reducing valve and a control valve, an
eventual pressure rise could activate the safety valve.
Motorized
Valve
PRV
Solenoid
Valve
PRV
Inlet Side
Outlet Side
Safety
Valve
Safety
Valve
Control
Valve
Control
Valve
Equipment
Equipment
PRV
PRV
